Table 1 Baseline data of the two treatment groups.

Women/men

43/33

44/30

Age ± SD

51.6 ± 10.2

50.2 ± 10.6

Diagnosis

Spondylolysis/-olisthesis

17

13

Disk herniation

2

4

Spinal stenosis

26

18

Degenerative disc disease

28

34

Non-union of previous fusion

3

5

Treatment

Decompression and posterior fusion

27

24

Posterior fusion without decompression

16

21

Posterior lumbar interbody fusion

33

29

Levels fused

1

53

43

2

19

27

3

4

2

4

0

2